Harlequin Shrimp at Work

Harlequin Shrimp (Hymenocera picta or H. elegans) preying on starfish

I love the way Harlequin Shrimp move – their little abdomens waggle – like bobbleheads in reverse – bobblebutts! And the “wax on – wax off” movement with their claws – too cute! However, once you get past their looks, it gets a little gruesome because Harlequin Shrimp are voracious predators of starfish. I say gruesome because they don’t put a quick kill on them. No, they flip the starfish over so it can’t walk away then proceed to consume it, still alive, one… leg… at… a… time. EEEK!!

In 18 years of diving the Indo-Pacific, we have only seen about a half dozen pairs of these tiny, colorful shrimp. Some sightings were serendipitous, found while our guides and we were turning over rocks. Other times, our guides had been showing the apparently site-attached shrimp to divers over some period of time.

My favorite encounter was in 2009 in Lembeh Strait, Indonesia. Ned and our guide Liberty gave up a muck dive to accompany me to one of the coral-covered sites near the opening of the Strait so I could pursue my obsession with Convict Fish. They turned rocks while I stalked a plankton-picking swarm of juvenile fish. About half way into the dive, Liberty appeared, beckoning me to follow. I knew it had to be good if he took the time to come find me and there they were, two Harlequin shrimp dragging a starfish. Liberty had uncovered them when he lifted a dead piece of plate coral. The starfish was already missing a leg, like maybe they had stopped for a snack on their way home with the catch.

Harlequin Shrimp flips starfish over

This was the first time we had ever seen shrimp with such a large piece of unconsumed starfish and it was fascinating to watch them working together to move the much larger animal that was capable of moving (granted, slowly) on its own. I tried not to think about the fate of the starfish – we’ve seen a lot of predation and it normally doesn’t bother me – maybe because it is usually quick. You can click here to watch the teamwork video on our Blennywatcher YouTube Channel or watch it here: